The mechanism of the effect of V doping on the thermoelectric properties of ZnO ceramics

In this paper, the mechanism of the effect of V doping on the thermoelectric properties of ZnO is studied by experimental test and first principles calculation. The results show that the carrier concentration and conductivity increase significantly after V doping, which is mainly due to the donor effect caused by V substituting for Zn site, and the band gap becomes narrower. Due to the influence of 3d orbit of V ion, the density of states near Fermi level increases. The effective mass decreases and the Seebeck coefficient decreases with V doping. The thermal conductivity decreases with the decrease of lattice thermal conductivity, which is mainly due to the decrease of Young's modulus due to the change of strain and stress field caused by V doping. While the power factor increases, the thermal conductivity decreases, and the ZT value increases significantly in the whole temperature range, with the highest value reaching 0.302 ​at 873 ​K for Zn0.985V0.015O, which is 3.02 times of undoped ZnO.